Method and control system for a displacement device, with distance measurement in order to detect obstacles

ABSTRACT

A method and a system for control of a displacement device for a fifth wheel coupling which coupling is disposed on a tractor vehicle are described, wherein the displacement device has a lower structure having at least one guide rail oriented in the direction of travel, a movable carriage which supports the fifth wheel coupling and engages the guide rail(s), and a control device connected to a motorized drive unit for displacing the carriage and also connected to an adjusting member for fixing the carriage with respect to the guide rail(s). The underlying problem of the invention was to devise a method and a control system whereby timely establishment of a sufficiently long gap between the tractor and the associated semi-trailer is possible. One means by which this problem is solved is with a method wherein distance measurement is carried out to detect an obstacle disposed ahead of the tractor, and the measurement signal is processed in the control device to yield a control signal, which is employed to actuate the motorized drive unit and/or the adjusting member.

FIELD OF INVENTION

The invention relates to a method for controlling a displacement devicefor a fifth wheel coupling disposed on a tractor vehicle, according tothe features in the claims. The invention further relates to aparticularly suitable control system for carrying out the inventivemethod for a displacement device.

BACKGROUND OF THE INVENTION

A displacement device of the general type contemplated is known, e.g.from DE 10 2005 060124 A1. With the aid of a motorized drive unit acarriage bearing the fifth wheel coupling can be displaced in thelongitudinal direction of the tractor vehicle on two parallel guiderails, and can be locked in a prescribed position. When the vehicle istraveling at rapid Autobahn speeds without appreciable curves, it isdesirable for the fifth wheel coupling to be positioned as close aspossible to the tractor cab, in order to minimize the gap between thecab and the front of the semi-trailer and thereby minimize vortexformation in this region. According to the cited known patentapplication, the control device of the displacement device is connectedto the vehicle control system, so that information relating to thevehicle speed can be retrieved and thus in normal operation the gapbetween the tractor and the semi-trailer can be adjusted appropriately.However, with this arrangement there is a problem in that whennegotiating a curve of relatively short radius the semi-trailer canswing past the cab under conditions of minimization of the gap betweenthe tractor and semi-trailer, and thereby a corner of the semi-traileris apt to strike against the cab. This problem also tends to arise insituations of panic braking sudden intense braking without compensatingmaneuvers; the panic braking can be taken into account by evaluation ofa braking signal which is input to the control device and converted intoan actuation of the displacement device to bring about extremely rapidrearward movement of the carriage so as to increase the length of thegap.

Other state of the art is disclosed in DE 10 2004 045662 A1, wherein thedisplacement device is associated with a position sensor whichdetermines the position of the carriage. The signal from the positionsensor is sent to a control device wherewith, if the gap between the caband the front of the semi-trailer is too short, the control device mayactuate the drive unit of the displacement device and thereby displacethe carriage rearward.

However, in practice it has been found that inputs in the form ofbraking signals and vehicle speed signals are not well suited to timelyrespond to panic braking. The reaction times required for the controlsystem are extremely short, often insufficient for the system to timelydisplace the fifth wheel coupling into a rearward position and therebyestablish the necessary distance between the cab and the front of thesemi-trailer.

SUMMARY OF THE INVENTION

Accordingly, the underlying problem of the invention was to devise amethod and a control system whereby timely establishment of asufficiently long gap between the tractor and the associatedsemi-trailer is possible.

This problem is solved according to the invention by a method whereindistance measurement is carried out to detect an obstacle disposed aheadof the tractor, and the measurement signal is processed in the controldevice to yield a control signal, which is employed to actuate themotorized drive unit and/or the adjusting member.

With displacement devices which are frequently used, the carriage isdisplaced on two parallel guide rails by means of a motorized driveunit, such as, e.g., a hydraulic cylinder, and, after the prescribedposition is reached, the carriage is fixed on both sides to the guiderails. Typically, the fixing means are comprised of an adjusting membere.g. a pneumatic or hydraulic cylinder, which moves locking pieces inthe direction of the guide rails, which pieces form-interlockinglyengage the guide rails. In the event of, e.g., intense braking orcollision, the motorized drive unit releases this locking of thecarriage.

Instead of a form-interlocking lock mechanism, it is also possible forthe motorized drive unit to be appropriately dimensioned such that onecan dispense with additional form-interlocking elements. With such anembodiment, the adjusting member will be understood to comprise ashutoff valve which traps the fluid present in the interior of thecylinder.

When the vehicle is traveling at high Autobahn speeds, the semi-trailerwill be drawn close to the tractor cab, by means of the displacementdevice, wherewith the gap between the cab and the front of thesemi-trailer will be held at its minimum length. This will minimizevortex formation and thereby will minimize fuel consumption. In theevent of a sudden steering maneuver, the fixing of the carriage will bereleased, and the carriage will be displaced rearward on the guiderails. Using the inventive method, the road path ahead of the vehicle ismonitored and obstacles in that path are detected. In this way it ispossible to increase the length of the gap between the cab and the frontof the semi-trailer even before the driver reacts.

Preferably the method of achieving this is that, when a prescribed firstreaction distance to the obstacle is reached, the control deviceswitches the motorized drive unit and/or the adjusting member into areadiness state. If the driver then initiates intense braking, possiblyaccompanied by a strong steering maneuver, the rearward displacement ofthe carriage can be effected without a time delay.

In the readiness status, one may cause, e.g., the startup of a hydraulicpump of the motorized drive unit. This makes the necessary systempressure available to the motorized drive unit which typically is ahydraulic cylinder, in order to move the carriage bearing the coupledsemi-trailer rearward under circumstances of intense braking of thevehicle.

Advantageously, when a second, shorter reaction distance is reached, thefixing of the carriage is released, and the carriage is displaced by themotorized drive unit into a rearward position. Under this scenario, thedriver still has not reacted, and the tractor and semi-trailercombination continues to approach the obstacle with undiminished speed.In this phase, the carriage is automatically forced into a rearwardposition on the guide rails, because at this point it is apparent thatintense braking or a sharp avoidance maneuver will follow.

Advantageously, the carriage will be fixed in the rearward position bymeans of the adjusting member. In particular, additional security can beachieved if locking pieces disposed on the adjusting memberform-interlockingly engage the guide rails, wherewith the carriage willnot be exclusively held in place by the motorized drive unit.

The invention is also realized in the form of a control system in whichthe control device is connected to a distance sensor which, when anobstacle is present ahead of the tractor vehicle, generates ameasurement value, and said control device cooperates with the driveunit and/or the adjusting member.

Preferably the distance sensor is a component of a distance measuringsystem of the vehicle. The distance measuring system serves to detectobstacles, and when the vehicle continues to approach an obstacle thedistance measuring system initiates braking without a reaction by thedriver. If such a distance measuring system is present, the controldevice can receive the necessary measurement value from that system.

The distance sensor may be a radar, lidar, or infrared sensor. Theunderlying principle of radar involves electromagnetic waves in theradio frequency range which are sent out in a so-called primary signaland when reflected by objects a secondary signal is generated which isreceived and evaluated. Lidar stands for “light detection and ranging”,also used for measurement of distances and speeds; it is analogous toradar, but instead of radio waves as in radar, laser light is used.

The distance maintenance system may also be a component of a pathfollowing system, or may comprise a path following system. In this casethe lane line comprises the obstacle. The path following system reactsby sending out a signal when the tractor moves away from the lane linewithout any appreciable steering action. This signal can also beutilized to shift the displacement system into a readiness state and/orto initiate a displacement of the carriage into a rearward position,because, after the vehicle departs from the lane line, e.g. due todriver fatigue, frequently this is followed by a sudden appreciablesteering action, in order to bring the tractor back into accord with thelane line.

BRIEF DESCRIPTION OF THE DRAWINGS

For the sake of better understanding, the invention will be described inmore detail hereinbelow with reference to three Figures.

FIG. 1 is a lateral view of a tractor vehicle with a displacement deviceand with a semi-trailer coupled to the tractor, according to the stateof the art;

FIG. 2 is a bottom view of the displacement device illustrated in FIG.1; and

FIG. 3 is a schematic lateral view of a tractor and semi-trailercombination provided with the inventive control system.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic lateral view of a tractor and semi-trailercombination with a tractor vehicle 2 and a semi-trailer 14 mechanicallycoupled to the tractor. The mechanical connection between the vehicles 2and 14 is accomplished via a fifth wheel coupling 3 which is disposed ona carriage 5 and which can be displaced in the longitudinal direction ofthe tractor vehicle on two parallel guide rails 4 disposed at a mutualdistance. The displacement of the fifth wheel coupling 3 occurs duringtravel of the vehicle, via a special motorized drive unit 7 in the formof a hydraulic cylinder, and serves in particular to adjust the lengthof the gap W between the rear side of the tractor cab 13 and the front15 of the semi-trailer.

The displacement device 1 is illustrated in an enlarged bottom view inFIG. 2. An adjusting member 8 disposed perpendicularly to the guiderails 4 is disposed on the carriage 5; locking pieces 16 a, 16 b whichform-interlockingly engage complementary receiving members (not shown)associated with the guide rails 4 are disposed at the ends of member 8,serving to fix the carriage 5 on the guide rails 4. Before the carriage5 is moved by the motorized drive unit 7, the locking pieces 16 a, 16 bare retracted by the adjusting member 8, thereby releasing themechanical locking.

In FIG. 3 there may be seen a rearward position 11 a and a forwardposition 11 b of the carriage 5 and thus of the front 15 of thesemi-trailer, where for the sake of conventional graphic clarity theforward position 11 b is drawn in dotted lines. The forward position 11b corresponds to the minimum gap length W₁ and the rearward position 11a corresponds to the maximum gap length W₂. The size of the minimum gaplength W1 is set in such a way that with this gap length it would not bepossible to fully swing the front 15 of the semi-trailer withoutcollision with the tractor cab 13.

The inventive control system illustrated in FIG. 3 is comprised of adistance sensor 12 disposed on the front side of the tractor 2, whichsensor monitors the road ahead of the tractor 2 for possible obstacles9. For this purpose, the distance sensor 12 sends out a measuring lobesignal 17 forwardwise in the direction of travel of the tractor 2. Assoon as the distance sensor 12 detects an obstacle located within thereaction distance X₁, a corresponding signal is sent to an electroniccontrol device 6 which promptly actuates a hydraulic pump 10 or acomparable motor.

If the driver does not show an appropriate reaction to obstacle 9 beforethe distance is reduced to a second reaction distance X₂, the carriage 5bearing the front part of the semi-trailer 14 is retracted rearward bythe motorized drive unit 7, and the maximum gap length W₂ isestablished. After the maximum gap length W₂ has been effected, extremeavoidance maneuvers are possible, because the front 15 of thesemi-trailer can swing past the tractor cab 13 without striking it.

LIST OF REFERENCE NUMERALS

-   1 Displacement device-   2 Tractor vehicle-   3 Fifth wheel coupling-   4 Guide rail-   5 Carriage-   6 Control device-   7 Motorized drive unit-   8 Adjusting member-   9 Obstacle-   10 Hydraulic pump-   11 a Rearward position of the carriage-   11 b Forward position of the carriage-   12 Distance sensor-   13 Tractor cab-   14 Semi-trailer-   15 Front of the semi-trailer-   16 a, 16 b Locking piece on the adjusting member-   17 Measuring lobe-   X₁ First reaction distance-   X₂ Second reaction distance-   W Length of the gap between the tractor and the semi-trailer-   W₁ Minimum gap length-   W₂ Maximum gap length

1. A method of controlling a displacement device for a fifth wheel coupling which coupling is disposed on a tractor vehicle, wherein the displacement device comprises: a lower structure having at least one guide rail oriented in the direction of travel, a movable carriage which supports the fifth wheel coupling and engages the guide rail(s), and a control device connected to a motorized drive unit for displacing the carriage and also connected to an adjusting member for fixing the carriage with respect to the guide rail(s); comprising the steps of: carrying out a distance measurement to detect an obstacle disposed ahead of the tractor, and processing the measurement signal in the control device to yield a control signal, which is employed to actuate the motorized drive unit and/or the adjusting member.
 2. The method according to claim 1; wherein when a prescribed first reaction distance (X₁) to the obstacle is reached the motorized drive unit and/or the adjusting member is/are switched into a state of readiness.
 3. The method according to claim 1; wherein in a state of readiness a hydraulic pump starts up the motorized drive unit.
 4. The method according to claim 1; wherein when a prescribed second reaction distance (X₂) is reached the fixing of the carriage is released, and the carriage is displaced by the motorized drive unit into a rearward position.
 5. The method according to claim 4; wherein when the carriage is in the rearward position it is fixed by means of the adjusting member.
 6. A control system comprised of: a displacement device for a fifth wheel coupling disposed on a tractor vehicle, wherein the displacement device comprises: a lower structure having at least one guide rail oriented in the direction of travel, a movable carriage which supports the fifth wheel coupling and engages the guide rail(s), and a control device connected to a motorized drive unit for displacing the carriage and also connected to an adjusting member for fixing the carriage with respect to the guide rail(s); wherein the control device is connected to a distance sensor which, when an obstacle is present ahead of the tractor vehicle, generates a measurement value, and said control device cooperates with the drive unit and/or the adjusting member.
 7. The control system according to claim 6; wherein the distance sensor is a component of a distance measuring system in or on the tractor.
 8. The control system according to claim 6; wherein the distance sensor is a radar sensor, lidar sensor, or infrared sensor.
 9. The control system according to claim 6; wherein the distance sensor is a component of a path following system for the tractor.
 10. The control system according to claim 7; wherein the distance sensor is a radar sensor, lidar sensor, or infrared sensor.
 11. The method according to claim 2; wherein when a prescribed second reaction distance (X₂) is reached the fixing of the carriage is released, and the carriage is displaced by the motorized drive unit into a rearward position.
 12. The method according to claim 3; wherein when a prescribed second reaction distance (X₂) is reached the fixing of the carriage is released, and the carriage is displaced by the motorized drive unit into a rearward position.
 13. The method according to claim 11; wherein when the carriage is in the rearward position it is fixed by means of the adjusting member.
 14. The method according to claim 12; wherein when the carriage is in the rearward position it is fixed by means of the adjusting member.
 15. The control system according to claim 10; wherein the distance sensor is a component of a path following system for the tractor. 